In known rocket engines of this type, because of the very high temperatures (of the order of 3300° C.) reached in said combustion chamber, the structure of the walls is particularly complex with networks of ducts for circulating a cooling fluid which, incidentally, may be said fuel itself. Examples of known walls are described, for example, in documents FR-A-2 773 850, FR-A-2 774 432, FR-A-2 791 589. In addition, the structure of said walls is not uniform but by contrast varies along the axis of the engine, according to the temperature at that point. Finally, particularly on account of the fact that the fuel is used as a cooling fluid and can circulate in the two opposite directions, these known engines require complex fuel supply manifolds.